Project 1 - Abstract Chronic infections, such as HBV, HCV, HIV, Tb, malaria and others, are major causes of morbidity and mortality. Recent advances in pharmacological and immunological treatments have revealed new opportunities to cure some of these persisting infections. A single patient, Timothy Brown, cured of HIV using a bone marrow (BM) transplant in 2008 is proof of concept that cure for HIV is possible. Subsequent trials using cellular therapies demonstrated feasibility of such approaches, but no cures were achieved. Nevertheless, catalyzed in part by these initial observations in HIV and by progress in immunotherapy of cancer, there are now considerable efforts focused on adoptive cell therapies (ACT) for HIV. Despite major successes of ACT for some forms of cancer, a major barrier to success for cancers and especially for HIV is T cell exhaustion. Indeed, when CAR T cells fail in cancer patients, T cell exhaustion is a major underlying mechanism7-9 and T cell exhaustion is central to immune failures in HIV control11,12,64. Thus, the central goal of Project 1 is to identify molecular pathways of T cell exhaustion that can be targeted to improve the function and/or durability of T cells during cellular therapy of chronic viral infection. Our goal is to identify mechanisms of T cell exhaustion that can be targeted to improve function and durability of ACT for HIV. We will first test these ideas in a mouse model of chronic viral infection and then move promising candidates to testing in HIV infected humanized mice while also dissecting underlying molecular mechanisms. We will test the overall hypothesis that molecular pathways associated with T cell exhaustion can be effectively targeted through genetic engineering to improve the next generation of ACT approaches for HIV. We will test this hypothesis through the following Aims: SA1. TO IDENTIFY AND TEST IN VIVO KEY GENES AND PATHWAYS THAT WILL IMPROVE THE FUNCTION AND/OR HOMING OF T CELLS DURING ACT OF CHRONIC VIRAL INFECTION AND HIV. We hypothesize that pathways that regulate effector function and/or homing can be targeted to improve T cell efficacy during ACT of chronic viral infection. SA2. TO IDENTIFY AND TEST IN VIVO GENES AND PATHWAYS THAT WILL IMPROVE LONG-TERM DURABILITY, DIFFERENTIATION AND RECALL CAPACITY OF T CELLS FOR ACT DURING CHRONIC VIRAL INFECTION AND HIV. We hypothesize that specific persistence and/or memory related pathways that are defective in T cell exhaustion can be targeted to improve the durability and effectiveness of ACT in chronic viral infection. Thus, the goal of SA2 is to identify and target pathways that improve the optimal long-term persistence, differentiation and recall capacity of T cells in ACT of chronic viral infection. The long-term goal of Project 1 is to improve the next generation of CAR T cell therapies for HIV. The studies proposed will not only identify important new targets for ACT of HIV and dissect underlying mechanisms, but will also establish a platform for future efforts at improving cellular therapies based on preventing or reversing T cell exhaustion.